Description: (from applicant's Abstract) While considerable advances have been made in the treatment of the injury of HIV infection and its complications, HIV related wasting continues to be a frequent and devastating biologic response. The currently accepted definition of wasting, the loss of 10 percent body weight, is inadequate to diagnose wasting in a time efficient manner, when intervention may be most effective. There is a growing consensus that wasting would be better defined as a process that is characterized by both early and late biologic phases. Although body composition biomarkers have been identified and tested as late phase indicators, biomarkers consistent with early wasting processes have not been previously identified or tested. Therefore, the purpose of this study is to establish reliable and sensitive clinical biomarkers that signal early HIV wasting, or wasting that occurs prior to the actual loss of body weight and to changes in body composition. Using a retrospective descriptive design, the specific aims are 1) to examine the patterns of variability and sensitivity of early HIV wasting clinical biomarkers and 2) to examine the relationships between early clinical biomarkers of HIV wasting, late wasting biomarkers, age and gender. Subjects who have been diagnosed as wasted will be recruited from four treatment sites in southern Nevada. Early and late serological and body composition biomarkers data will be collected for the 18 months immediately preceding the diagnosis of HIV wasting via a retrospective chart review process. It is anticipated that this feasibility study will provide additional, initial information about early clinical biomarkers of HIV wasting. In addition, this data will also provide valuable information regarding the feasibility and potential of the early ant late wasting syndrome model that is presented, and help identify components of the model that merit further testing. A model that is able to accurately predict both early and late-phase wasting processes using relevant clinical biomarkers would enable health care providers to initiate early diagnosis and treatment of HIV wasting, and subsequently improve quality of life and mortality in persons living with HIV.